Ouch, get well soon

A real long shot - times could correspond with local load increasing, thus voltage drops, auto tap switching on the transformer kicks in to increase voltage, arcing contact, plenty of RF noise. Although I would hope the supply company would be on top of that. This is why I suggest using the radio right outside the substation. That will give a good indication that it might/might not be responsible.

Looks like a distribution unit so will most likely be fixed tap. Still could be chucking out noise though, dodgy core lamination's, even circuit breaker contact arcing.

My reasoning is that the problem starts early morning and stops last thing at night. Day in Day out ... which the OPs graphs show. If it was a fixed tap then the problem would be continuous. The location of the BT cabinet and duct so close gives reason to suspect it.

Some local distribution points do switch taps - father-in-law used to design transformers for use in power distribution and he has come up with some real horror stories.

Not saying they don't exist but they are not that common and generally industrial consumers on their own feeds.
Most distribution units have an off load manual tap changer compared with primary sites which are automatic on load, allows for easier voltage control from a central location otherwise you run into issues with the distribution unit competing with the primary.

As I said could be a noisy transformer core, switchgear contacts or bushings arcing or maybe a dodgy joint.

here is a dmt screenshot of what it should look like. Seems to be the higher frequencies effected.

http://img.photobucket.com/albums/v228/Lemzip/dmt201...

I know this is not the solution you would like to here, but have you tried forcing a different adsl mode during the times the noise/interference is affecting your line ? (switch from adsl2+ to g.dmt? or adsl2) as the frequencies will be different on the other 2,and there fore maybe be unaffected or less affected,i have a rein type issue also, i would switch mode as i suggested but for whatever the reason the easynet exchange kit doesn't or didn't like it, (ie it locked me to adsl g.dmt) until i got it manually swapped to adsl2+ again

"I have tried the tuning in a AM radio to 612Khz and walking around but iat night i only get a french lady "

Not REIN then.

Just noticed and im not sure if this can point me in the right direction but it seems the higher frequencies are affected.

ie from around 1690kHz to 2000KHz. The wierd thing is from 5pm today it was okay until now, 11pm.

My snr seems to be better at night then during the day which is opposite the usual issue.

After suffering from Rein for almost 2 years in 2007 in Bradley Stoke, we (Paul Hucklbridge fro OR and myself) eventually found the cause to be a tripler in a portable television half a mile away. It was wiping out 100% of the signal for >1000 people. So don't automatically think it's your neighbours, anywhere along the line will kill it.

To find it nice and quick (yes, we had another occurence about a year later, this was a bad telephone answering machine wall-wart), found this one in an hour. You really need to get the AM radio out, you have to pick a frequency (I found around 600Khz to be good) that gets a nice loud buzz when you get the rein issue. Stick the radio right next to the phone socket. Make sure it vanishes completely when rein stops.

Then I'm afraid to you need to trawl ebay. Your after an ADF, mines a Nova-tech 'Nova-Pal'. I paid about 20 quid for it. Dial in the same frequency to this as your am radio. Next time the rein hits, power it on and get your shoes on. Turn the gain up full and start walking in the direction of the highest signal, then back the gain off until you find the exact source. I could trace it to within a meter, but you can usually narrow it down to one or two houses in about 10 minutes. Then be polite to the occupents! You need to work with them, usually they are suffering from issues themselves.

Incidently using a normal AM radio to do this is useless as they all have agc, you can spend years walking on top of phone lines and get nowhere (I did!).

Good Luck!
Tim

Here is a google link to a picture of the unit I have:
http://www.google.co.uk/imgres?imgurl=http://pmimage...